1. Field
The present invention relates to a pattern forming method for forming a pattern on a substrate.
2. Description of Related Art
In recent years, a pattern forming method using an optical imprint method has been attracting attention (Jpn. Pat. Appln. KOKAI Publication No. 2001-68411). The optical imprint method includes a step of applying light curable resin onto a substrate, a step (alignment) of positioning the substrate and a template (also called a mold or an original plate), a step (imprint) of contacting the light curable resin with the template, a step of curing the light curable resin by irradiation of light, a step (demold) of separating the template from the cured light curable resin (resin pattern), and a step of etching the substrate using the resin pattern as a masked.
The following method is one of optical imprint methods expected to be most applicable on semiconductor lithography.
In this method, at first, liquid light curable resin is discharged toward (applied onto) a substrate by inkjet method, to form liquid light curable resin on one-shot of area (shot area) of the substrate. The discharge amount (drop amount) of the liquid light curable resin is calculated in consideration of a density of pattern (concave portion of a concave/convex pattern) formed on the template, and the like. contacted with the template. Thereafter, the template is more closed to the substrate. This condition is maintained for a constant time period such that the liquid light curable resin spreads into the concave portion of the concave/convex pattern of the template, and when the constant time is passed, light (UV) is irradiated on the liquid light curable resin to cure the liquid light curable resin. Thereafter, the template is separated from the cured light curable resin.
However, the conventional method described above has a problem as follows. After the liquid light curable resin is formed on the substrate, volatilization of the light curable resin proceeds until the liquid light curable resin is cured, which results in thinning of the light curable resin.
Therefore, even if the light curable resin is discharged (applied) on the substrate in accordance with a distribution quantity of the drop amount of the light curable resin which is calculated in consideration of the density of pattern (concave portions of the concave/convex pattern) formed on the template, the concave portions of the concave/convex pattern, a portion not filled with the light curable resin arises in the concave portions of the concave/convex pattern. The portion not filled with the light curable resin causes a pattern defect (unfilled defect) depending on size and shape of the portion not filled with the light curable resin.